The Arizona-Sonora Desert Museum has a digital library containing thousands of photographs of plants and animals. The digital library is an interactive site that has a kidâs page with videos, animal sounds, and games.
The photo is courtesy of: http://members.multimania.nl/onager/ballista.htmlMangonelThe Mangonel is what many people think of when they think of a catapult. From the Latin word manganon meaning engine of war. The Mangonel was invented by the Romans in 400 BC. The Mangonel consists of a long wood arm with a bucket (early models used a sling) with a rope attached to the end. The arm is then pulled back (from natural 90o angle) then energy was stored in the tension of the rope and the arm. Then the bucket would be loaded.
Onager, in weaponry, ancient Roman torsion-powered weapon, similar to a catapult. It consisted of a single vertical beam thrust through a thick horizontal skein of twisted cords. The skein was twisted tight by geared winches, and the beam was then pulled down to a horizontal position, further increasing the twist (and thus the torsion) of the skein.